Sub-mm wave emission in beam-plasma experiments on GOL-3 facility

Fast plasma heating in a multi-mirror magnetic trap by a high-current beam of relativistic electrons is a promising way to achieve fusion-grade plasma parameters. A high-level Langmuir turbulence develops during the beam-plasma interaction. These high-energy-density plasma oscillations can generate electromagnetic (EM) radiation in a wide frequency range extending from the plasma frequency to its 2nd harmonic. Thus the spectrum of EM emission can achieve 1 THz at 3·10¹⁵ cm^-3 plasma density. The first experiments on the generation of sub-mm waves by a beam-heated plasma carried out at the GOL-3 facility were presented in [1]. Here we present results on sub-mm wave generation for plasma densities 10¹⁴-10¹⁵ cm^-3 during injection of a relativistic electron beam (≤ 0.8 MeV, 30 kA, ~10 μs).